Process for isomerizing 3-pentenenitrile to 4-pentenenitrile



United States Patent Oifice 3,542,847 PROCESS FOR ISOMERIZINGS-PENTENENITRILE TO 4-PENTENENITRILE William C. Drinkard, In,Wilmington, and Richard V. Lindsey, Jr., Hockessin, Del., assignors toE. I. du Pont de Nemours and Company, Wilmington, Del., a corporation ofDelaware No Drawing. Continuation-impart of application Ser. No.679,608, Nov. 1, 1967. This application Sept. 15, 1969, Ser. No. 858,098

Int. Cl. C07c 121/30 U.S. Cl. 260-465.9 7 Claims ABSTRACT OF THEDISCLOSURE Process of isomerizing B-pentenenitriles to 4-pentenenitrileusing platinum or palladium catalysts having a valence of +2 or less andof adding hydrogen cyanide to nonconjugated carbon-carbon double bondssuch as in 4-pentenenitrile at from 25 to 200 C. using catalysts of thestructure Pd(PX where X is R or OR and R is an alkyl or aryl group of upto 18 carbon atoms.

CROSS-REFERENCE TO RELATED APPLICATION This application is acontinuation-in-part of application Ser. No. 679,608, filed on Nov. 1,1967, by William Charles Drinkard, Jr., and Richard V. Lindsey, Jr., nowabandoned.

DESCRIPTION OF THE PRIOR ART It is known that the addition of hydrogencyanide to double bonds adjacent an activating group such as a nitrileor acyloxy group, proceeds with relative ease. However, the addition ofhydrogen cyanide to nonactivated double bonds proceeds only withdifiiculty, if at all, and normally requires the use of high pressuresof about 1,000 p.s.i. or more and high temperatures in the range of 200to 400 C. U.S. Pat. No. 2,571,099, issued Oct. 16, 1951 to Paul Arthur,Jr., and Burt Carlson Pratt, discloses a technique which involves theuse of nickel carbonyl with or without the addition of a tertiary arylphosphine or arsine. This process suffers from producing a relativelyhigh percentage of undesirable polymeric products when applied tomonoolefinic starting materials and a relatively poor yield in allcases. Furthermore, this process is not satisfactory for the productionof adiponitrile from 3- or 4-pentenenitrile. The selective formation of4-pentenenitrile from 3-pentenenitrile rather than the thermodynamicallymore stable Z-pentenenitrile is believed to be unknown in the art.

SUMMARY OF THE INVENTION The present invention provides a process whichproduces nitriles or dinitriles from olefins in high yield, under mildconditions, with minimal formation of polymer.

The hydrocyanation process of the present invention is generallyapplicable 'to nonconjugated unsaturated compounds of from 2 to 20carbon atoms having at least one ethylenic carbon-carbon double bond,which organic compounds are selected from the class consisting of ali-3,542,847 Patented Nov. 24, 1970 and wherein each open bond is connectedto hydrogen or an aliphatic or aromatic hydrocarbon group, wherein thecarbon-carbon double bond is insulated from the aforesaid group by atleast 1 carbon atom. The 3-pentenenitrile, 4-pentenenitrile and2-methyl-3-butenenitrile are preferred. Suitable unsaturated compoundsinclude monoolefins and monoolefins substituted with groups which do notattack the catalyst such as cyano. These unsaturated compounds includemonoolefins containing from 2 to 20 carbon atoms such as ethylene,propylene, butene-l, pentene-2, heXene-2, etc., and substitutedcompounds such as styrene, a-methyl styrene, 3-pentenenitrile, and4-pentenenitrile. The process also finds special advantage in theproduction of Z-methylglutaronitrile from 2-methyl-3-butenenitrile.

In the preferred process of the present invention wherein adiponitrileis formed from 3-pentenenitrile the reaction proceeds in two steps. Thefirst step involves the isomerization of 3-pentenenitrile to4-pentenenitrile followed by the addition of hydrogen cyanide to4-pentenenitrile to form adiponitrile.

The first step is catalyzed by palladium or platinum compounds having avalence of +2 or less such as palladium dihalides, and the hereinbelowdefined platinum compounds and palladium compounds. In carrying out theisomerization step using (0) valent palladium or platinum an acidpreferably also is present. Suitable acids include hydrogen cyanide,trifiuoroacetic acid, hydrochloric acid, sulfuric acid, etc., as Well asthe hereinbelow defined compounds for use as promoters for thehydrocyanation reaction wherein a palladium catalyst is used.

The preferred isomerization process of converting 3- pentenenitrile to4-pentenenitrile is carried out in the presence of a compound of thegeneral formula M(PX wherein M is Pd or Pt, wherein X is OR or R whereinR is selected from the class consisting of alkyl and aryl groups havingup to 18 carbon atoms. The hydrocyanation step is carried out in thepresence of a compound of the formula Pd(PX wherein X is defined asabove. If desired, any of the Xs may be cojoined.

The catalyst preferably is prepared prior to use. However, the catalystcan be prepared in situ by any of several methods such as by adding adivalent palladium or platinum compound such as a' palladium or platinumhalide, palladium or platinum acetylacetonate, palladium or platinumacetate; a compound of the formula PX where X has the meaning definedabove and a reducing agent such as Al(CH CI-l zinc metal, iron,aluminum, magnesium, hydrazine, or sodium borohydride. While the amountof 3 catalyst present is not critical, it is generally preferable thatexcess unsaturated compound be present.

The hydrocyanation or isomerization reaction can be carried out with orwithout a solvent. The solvent should be a liquid at the reactiontemperature and inert towards the unsaturated compound and the catalyst.Generally, such solvents are hydrocarbons such as benzene, xylene, ornitriles such as acetonitrile, benzonitrile, or adiponitrile.

The exact temperature used is dependent, to a certain extent, on theparticular catalyst being used, the particular unsaturated compoundbeing used and the desired rate. Generally, temperatures of from -25 C.to 200 C. can be used with from C. to 150 C. being the preferred rangefor both isomerization and hydrocyanation.

Either reaction may be carried out by charging a reactor with all of thereactants. In the case of hydrocyanation, preferably the reactor ischarged with the catalyst or catalyst components, the unsaturatedcompound and whatever solvent is to be used. The hydrogen cyanide gas isthen swept over the surface of the reaction mixture or bubbled into saidreaction mixture. Alternately, the hydrogen cyanide can be introduced inliquid form. If desired, when using a gaseous unsaturated organiccompound, the hydrogen cyanide and the unsaturated organic compound maybe fed together into the reaction medium. The molar ratio of unsaturatedcompound to catalyst generally is varied from about 10:1 to 2000:1unsaturated compound to catalyst for a batch operation. In a continuousoperation such as when using a fixed bed catalyst type of operation, amuch higher proportion of catalyst may be used such as 1:2 unsaturatedcompound to catalyst.

Optionally, a promoter may be used to activate the catalyst for thehydrocyanation reaction. The promoter generally is a boron compound or acationic form of a metal selected from the class consisting of zinc,cadmium, beryllium, aluminum, gallium, indium, thallium, titanium,zirconium, hafnium, erbium, germanium, tin, vanadium, niobium, scandium,chromium, molybdenum, tungsten, manganese, rhenium, thorium, iron andcobalt. Among these the cations of zinc, cadmium, titanium, tin,chromium, iron and cobalt are preferred. Suitable promoters ot this typeare salts of the metals listed above and include aluminum chloride, zincchloride, cadmium iodide, titanium trichloride, titanium tetrachloride,zinc acetate, ethyl aluminum dichloride, chromic chloride, stannouschloride, zinc iodide, nickel chloride, cerous chloride, cobaltousiodide, cadmium chloride, molybdenum dichloride, zirconium chloride,thorium chloride, aluminum chloride, ferrous chloride and cobaltouschloride.

The boron compounds are borohydrides or organoboron compounds, of whichorganoboron compounds are of the structure B(R) are preferred.

The borohydrides are the alkali metal borohydrides, such as sodiumborohydride and potassium borohydride, and the quaternary ammoniumborohydrides particularly the tetra (lower alkyl)ammonium borohydridesand borohydrides of the formula B H where n is an integer of from 2 to10, and B H J where m is an integer of from 4 to 10. When the boroncompounds have the structure B(R') R is selected from the classconsisting of H, aryl radicals of from 6 to 18 carbon atoms, lower alkylradicals of from 1 to 7 carbon atoms, and lower alkyl radicals of from 1to 7 carbon atoms substituted with a cyano radical. Generally, the casewhere R is phenyl, as in triphenyl borane, or phenyl substituted with anelectronegative radical is preferred.

The nitriles formed by the present invention are useful as chemicalintermediates. For instance, adiponitrile is an intermediate used in theproduction of hexamethylene diamine which is used in the production ofpolyhexamethylene adipamide, a commercial polyamide, useful in formingfibers, films and molded articles. Other nitriles can be converted tothe corresponding acids and amines which are conventional commercialproducts.

4 DESCRIPTION OF THE PREFERRED EMBODIMENTS Example I A 50 ml.,three-necked round bottom glass flask, fitted with a water cooled refluxcondenser connected to a Dry Ice trap, a gas inlet above the liquidlevel and a magnetic stirrer is set up in an oil bath maintained at 100C. The flask is purged with nitrogen gas and charged with 0.64 g. ofPdCl 3.7 g. of Al(C H 0.68 g. of SnCl ml. of P(OC H and g. of3-pentenenitrile. A stream of nitrogen gas is bubbled through liquidhydrogen cyanide contained in a 20 ml. flask cooled in an ice bath. Theresulting gas mixture is swept across the surface of the reactionmixture in the flask. The nitrogen gas flow is adjusted so that 0.2 ml.per hour of hydrogen cyanide (measured as a liquid at 0 C.) is fed tothe reaction flask. After 21 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 13.0 percent adiponitrile, 5.4 percent Z-methylglutaronitrile,and 1.4 percent ethylsuccinonitrile.

Example II A ml., three-necked round bottom glass flask, fitted with awater cooled reflux condenser connected to a Dry Ice trap, a gas inletabove the liquid level and a magnetic stirrer is set up in an oil bathmaintained at C. The flask is purged with nitrogen gas and charged with0.64 g. of PdCl 3.7 g. of AI(C H 0.68 g. of SnCl 15 ml. of P(OC H and 20g. of 3-pentenenitrile. A stream of nitrogen gas is bubbled throughliquid hydrogen cyanide contained in a 20 ml. flask cooled in an icebath. The resulting gas mixture is swept across the surface of thereaction mixture in the flask. The nitrogen gas flow is adjusted so that0.2 ml. per hour of hydrogen cyanide (measured as a liquid at 0 C.) isfed to the reaction flask. After 18 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 3.9 percent adiponitrile, 2.3 percent Z-methylglutaronitrile,and 1.1 percent ethyl succinonitrile.

Example III A 50 ml., three-necked round bottom glass flask, fitted witha water cooled reflux condenser connected to a Dry Ice trap, a gas inletabove the liquid level and a magnetic stirrer is set up in an oil bathmaintained at 70 C. The flask is purged with nitrogen gas and chargedwith 1.35 g. of Pd[P(OC H and 20 g. of 3-pentenenitrile. A stream ofnitrogen gas is bubbled through liquid hydrogen cyanide contained in a20-ml. flask cooled in an ice bath. The resulting gas mixture is sweptacross the surface of the reaction mixture in the flask. The nitrogengas flow is adjusted so that 0.2 ml. per hour of hydrogen cyanide(measured as a liquid at 0 C.) is fed to the reaction flask. After 20hours and 30 minutes the reaction is shunt down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 0.39 percent adiponitrile and 0.07 percent2-methylglutaronitrile.

Example IV A 50 ml., three-necked round bottom glass flask, fitted witha water cooled reflux condenser connected to a Dry Ice trap, a gas inletabove liquid level and a magnetic stirrer is set up in an oil bathmaintained at C. The flask is purged with nitrogen gas and charged with1.35 g. of Pd[P(OC H 0.14 g. of ZnCl 3.1 g. of P(OC H and 20 g. of3-pentenenitrile. A stream of nitrogen gas is bubbled through liquidhydrogen cyanide contained in a 20 ml. flask cooled in an ice bath. Theresulting gas mixture is swept across the surface of the reactionmixture in the flask. The nitrogen gas flow is adjusted so that 0.2 ml.per hour of hydrogen cyanide (measured as a liquid at 0 C.) is fed tothe reaction flask. After 28 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 8.8 percent adiponitrile, 4.9 percent Z-methylglutaronitrile,and 1.0 percent ethylsuccinom'trile.

Example V A 50 ml., three-necked round bottom glass flask, fitted with awater cooled reflux condenser connected to a Dry Ice trap, a gas inletabove the liquid level and a magnetic stirrer is set up in an oil bathmaintained at 100 C. The flask is purged with nitrogen gas and chargedwith 1.35 g. of Pd[P(OC H 0.19 g. of SnCl 3.1 g. of 'P(OC H and 20 g. of3-pentenenitrile. A stream of nitrogen gas is bubbled through liquidhydrogen cyanide contained in a 20 ml. flask cooled inan ice bath. Theresulting gas mixture is swept across the surface of the reactionmixture in the flask. The nitrogen gas flow is adjusted so that 0.2 ml.per hour of hydrogen cyanide (measured as a liquid at C.) is fed to thereaction flask. After 4.5 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 3.54 percent adiponitrile, 1.49 percent 2-methylglutaronitrile,and 0.37 percent ethylsuccinonitrile.

Example VI A 50 ml., three-necked round bottom glass flask, fitted witha water cooled reflux condenser connected to a Dry Ice trap, a gas inletabove the liquid level and a magnetic stirrer is set up in an oil bathmaintained at 100 C. The flask is purged .with nitrogen gas and chargedwith 1.35 g. of Pd[P(OC H 0.15 g. of TiCl and g. of 3- pentenenitrile. Astream of nitrogen gas is bubbled through liquid hydrogen cyanidecontained in a flask cooled in an ice bath. The resulting gas mixture isswept across the surface of the reaction mixture in the flask. Thenitrogen gas flow is adjusted so that 0.2 ml. per hour of hydrogencyanide (measured as a liquid at 0 C.) is fed to the reaction flask.After 21 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 6.82 percent adiponitrile, 2.60 percent Z-methylglutaronitrile,and 0.64 percent ethylsuccinonitrile.

Example VII A 50 ml., three-necked round bottom glass flask, fitted witha water cooled reflux condenser connected to a Dry Ice trap, a gas inletabove the liquid level and a magnetic stirrer is set up in an oil bathmaintained at 100 C. The flask is purged with nitrogen gas and chargedwith 1.35 Of Pd[P(OC H5)3]4, g. Of B(C6H5)3, 3.1 g. of P(OC H and 20 g.of 3-pentenenitrile. A stream of nitrogen gas is bubbled through liquidhydrogen cyanide contained in a flask cooled in an ice bath. Theresulting gas mixture is swept across the surface of the reactionmixture in the flask. The nitrogen gas flow is adjusted so that 0.2 ml.per hour of hydrogen cyanide (measured as a liquid at 0 C.) is fed tothe reaction flask. After 29 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 19.34 percent adiponitrile, 3.37 percentZ-methylglutaronitrile, and 0.46 percent ethylsuccinonitrile.

Example VIII A 50 ml., three-necked round bottom glass flask, fittedwith a Water cooled reflux condenser connected to a Dry Ice trap, a gasinlet above the liquid level and a magnetic stirrer is set up in an oilbath maintained at 100 C. The flask is purged with nitrogen gas andcharged with 1.35 g. Of Pd[P(OC3H5)3]4, g. Of B( 6 5)3 and g. Of3-pentenenitrile. A stream of nitrogen gas is bubbled through liquidhydrogen cyanide contained in a flask cooled in an ice bath. Theresulting gas mixture is swept across the surface of the reactionmixture in the flask. The nitrogen gas flow is adjusted so that 0.2 ml.per hour of hydrogen cyanide (measured as a liquid at 0 C.) is fed tothe reaction flask. After 29 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 25.05 percent adiponitrile, 5.19 percent2-methylglutaronitrile, and 0.76 percent ethylsuccinonitrile.

Example IX A 50 ml., three-necked round bottom glass flask, fitted witha water cooled reflux condenser connected to a Dry Ice trap, a gas inletabove the liquid level and a magnetic stirrer is set up in an oil bathmaintained at C. The flask is purged with nitrogen gas and charged with1.35 g. of Pd[P(OC H 0.34 g. of CrCl (tetrahydrofuranh, and 20 g. of3-pentenenitrile. A stream of nitrogen gas is bubbled through liquidhydrogen cyanide contained in a flask cooled in an ice bath. Theresulting gas mixture is swept across the surface of the reactionmixture in the flask. The nitrogen gas flow is adjusted so that 0.2 ml.per hour of hydrogen cyanide (measured as a liquid at 0 C.) is fed tothe reaction flask. After 24 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 9. 64 percent adiponitrile, 3.51 percent2-methylg1utar'onitrile, and 0.81 percent ethylsuccinonitrile.

Example X A 50 ml., three-necked round bottom glass flask, fitted with awater cooled reflux condenser connected to a Dry Ice trap, a gas inletabove the liquid level and a magnetic stirrer is set up in an oil bathmaintained at 60 C. The flask is purged with nitrogen gas and chargedWith 1.35 g. of Pd[P(OC H 0.24 g. of B(C H and 20 g. of3-pentenenitrile. A stream of nitrogen gas is bubbled through liquidhydrogen cyanide contained in a flask cooled in an ice bath. Theresulting gas mixture is swept across the surface of the reactionmixture in the flask. The nitrogen gas flow is adjusted so that 0.2 ml.per hour of hydrogen cyanide (measured as a liquid at 0 C.) is fed tothe reaction flask. After 19 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 20.14 percent adiponitrile, 3.37 percent2-methylglutaronitrile, and 0.37 percent ethylsuccinonitrile.

Example XI A 50 ml. three-necked round bottom glass flask, fitted With awater cooled reflux condenser connected to a Dry Ice trap, a gas inletabove the liquid level and a magnetic stirrer is set up in an oil bathmaintained at 100 C. The flask is purged with nitrogen gas and chargedwith 1.35 g. of Pd[P(OC 'H 0.13 g. of Mncl and 20 g. of3-pentenenitrile. A stream of nitrogen gas is bubbled through liquidhydrogen cyanide contained in a flask cooled in an ice bath. Theresulting gas mixture is swept across the surface of the reactionmixture in the flask. The nitrogen gas flow is adjusted so that 0.2 ml.per hour of hydrogen cyanide (measured as a liquid at 0 C.) is fed tothe reaction flask. After 20 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 4.84 percent adiponitrile, 2.34 percent Z-methylglutaronitrile,and 1.95 percent ethylsuccinonitrile.

Example XII A 50 ml., three-necked round bottom glass flask fitted witha water cooled reflux condenser connected to a Dry Ice trap, a gas inletabove the liquid level and a magnetic stirrer is set up in an oil bathmaintained at 100 C. The flask is purged with nitrogen gas and chargedwith 1.35 g. of Pd[P(OC H 0.13 g. of C001 and 20 g. of 3-pentenenitrile.A stream of nitrogen gas is bubbled through liquid hydrogen cyanidecontained in a flask cooled in an ice bath. The resulting gas mixture isswept across the surface of the reaction mixture in the flask. Thenitrogen gas flow is adjusted so that 0.2 ml. per hour of hydrogencyanide (measured as a liquid at C.) is fed to the reaction flask. After20 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 19.65 percent adiponitrile, 11.29 percentZ-methylglutaronitrile, and 1.95 percent ethylsuccinonitrile.

Example XIII A 50 ml., three-necked round bottom glass flask fitted witha water cooled reflux condenser connected to a Dry Ice trap, a gas inletabove the liquid level and a magnetic stirrer is set up in an oil bathmaintained at 100 C. The flask is purged with nitrogen gas and chargedwith 1.35 g. of Pd[P(OC H 0.42 g. of ZnCI and g. of 3- pentenenitrile. Astream of nitrogen gas is bubbled through liquid hydrogen cyanidecontained in a flask cooled in an ice bath. The resulting gas mixture isswept across the surface of the reaction mixture in the flask. Thenitrogen gas flow is adjusted so that 0.2 ml. per hour of hydrogencyanide (measured as a liquid at 0 C.) is fed to the reaction flask.After 29 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 18.1 percent adiponitrile, 9.9

percent Z-methylglutaronitrile, and 1.5 percent ethylsuccinonitrile.

Example XIV Example XV A ml., three-necked, round bottom glass flaskfitted with a water cooled reflux condenser connected to a Dry Ice trap,a gas inlet tube above the liquid level, and a magnetic stirrer is setup in an oil bath. The flask is purged with nitrogen gas and chargedwith 1.8 g. of

PdCl 20 g. of 3-pentenenitrile and 1 ml. of glacial acetic acid, andfurther purged with nitrogen gas, after which the oil bath is heated toC. for 20 hours at which time the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 7.2 percent 4-pentenenitrile.

Example XVI A 50 ml., three-necked round bottom glass flask fitted witha water cooled reflux condenser connected to a Dry Ice trap, an inlettube above the liquid level, and a magnetic stirrer is set up in an oilbath. The flask is purged with nitrogen gas, charged with 2.6 g. of PtCland 20 g. of 3-pentenenitrile, and further purged with nitrogen gasafter which the oil bath is heated to 80 C. for 20 hours at which timethe reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 0.7 percent 4-pentenenitrile.

Example XVII A 50 ml., three-necked, round bottom glass flask fittedwith a water cooled reflux condenser connected to a Dry Ice trap, a gasinlet above liquid level and a magnetic netic stirrer is set up in anoil bath. The flask is purged with nitrogen gas, charged with 0.62 g. ofPt[P(C H 0.1 ml. of pure trifluoroacetic acid, and 20 g. of 3-pentene- 8nitrile; and further purged with nitrogen gas after which the oil bathis heated to C. for 24 hours at which time the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 1.0 percent 4-pentencnitrile.

Example XVIII A 50 ml., three-necked round bottom glass flask, fittedwith a water cooled reflux condenser connected to a Dry Ice trap, a gasinlet above liquid level and a magnetic stirrer is set up in an oil bathmaintained at 80 C. The flask is purged with nitrogen gas and chargedwith 1.35 g. of Pd[P(Oc5H5)3]4, g. Of B(C6H5)3, and g. Ofdicyclopentadiene. A stream of nitrogen gas is bubbled through liquidhydrogen cyanide contained in a 20 ml. flask cooled in an ice bath. Theresulting gas mixture is swept across the surface of the reactionmixture in the flask. The nitrogen gas flow is adjusted so that 0.2 ml.per hour of hydrogen cyanide (measured as a liquid at 0 C.) is fed tothe reaction flask. After 19 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains about 1 percent of hydrocyanated dicyclopentadiene. Product wasidentified by infrared and nuclear magnetic resonance spectra.

Example XIX A 50 ml., three-necked round bottom glass flask, fitted witha water cooled reflux condenser connected to a Dry Ice trap, a gas inletabove liquid level and a magnetic stirrer is set up in an oil bathmaintained at 80 C. The flask is purged with nitrogen gas and chargedwith 1.35 g. of PCl[P(OC H5)3]4, g. of B(CGI'I5)3, and Of styrene. Astream of nitrogen gas is bubbled through liquid hydrogen cyanidecontained in a 20 ml. flask cooled in an ice bath. The resulting gasmixture is swept across the surface of the reaction mixture in theflask. The nitrogen gas flow is adjusted so that 0.2 ml. per hour ofhydrogen cyanide (measured as a liquid at 0 C.) is fed to the reactionflask. After 19 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains about one percent of hydrocyanated strene. Product wasidentified by infrared and nuclear magnetic resonance spectra.

Example XX A 50 ml. three-necked, round bottom glass flask, fitted witha water cooled reflux condenser connected to a Dry Ice trap, an inlettube above the liquid level and a magnetic stirrer is set up in an oilbath. The flask is purged with nitrogen gas and charged with 0.26 g. ofPd[P(OC H 0.07 g. of ZnCl and 20 g. of 3- pentenenitrile and 1 ml. oftriphenylphosphite, and further purged with nitrogen gas after which theoil bath is heated to 80 C. for 24 hours at which time the reaction isshut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 2.5 percent 4-pentenenitrile.

Example XXI A 50 ml., three-necked, round bottom glass flask, fittedwith a water cooled reflux condenser connected to a Dry Ice trap, a gasinlet above the liquid and a magnetic stirrer is set up in an oil bathmaintained at 100 C. The flask is purged with nitrogen gas and chargedwith 1.35 g. of Pd[P(OC H 0.24 g. of B(C H and 20 g. of 3-pentenenitri1efree of 4- pentenenitrile. A stream of nitrogen gas is bubbled throughliquid hydrogen cyanide contained in a 20 ml. flask cooled in an icebath. The resulting gas mixture is swept across the surface of thereaction mixture in the flask. The nitrogen gas flow is adjusted so that0.2 ml. per hour of hydrogen cyanide (measured as a liquid at C.) is fedto the reaction flask. After 20 hours the reaction is shut down.

Twenty-five minutes after startup a 2 ml. sample of the crude reactionmixture is removed from the reaction flask and found by gaschromatographic analysis to contain 4.94 percent 4-pentenenitrile.

After shut down the gas chromatographic analysis indicates that thecrude reaction mixture contains 4.64 percent adiponitrile, 0.82 percentZ-methylglutaronitrile, and 0.17 percent ethylsuccinonitrile and 5.59percent 4- pentenenitrile.

Example XXII A 50 ml., three-necked round bottom glass flask, fittedwith a water cooled reflux condenser connected to a Dry Ice trap, a gasinlet above the liquid level and a magnetic stirrer is set up in an oilbath maintained at 100 C. The flask is purged with nitrogen gas andcharged with 1.35 g. of Pd[P(OC H 1 2.0 g. of 2-methyl-3-butenenitrile,and 0.24 g. of B(C H A stream of nitrogen gas is bubbled through liquidhydrogen cyanide contained in a 20 ml. flask cooled in an ice 'bath. Theresulting gas mixture is swept across the surface of the reactionmixture in the flask. The nitrogen gas flow is adjusted so that 0.2 ml.per hour of hydrogen cyanide .(measured as a liquid at 0 C.) is fed tothe reaction flask. After 44 hours the reaction is shut down.

Gas chromatographic analysis indicates that the crude reaction mixturecontains 1.44 percent adiponitrile, 55.63 percentZ-methylglutaronitrile, and 0.04 percent ethylsuccinonitrile.

Example XXIII The reaction flask, as described in Example XXII, ischarged with 1.35 g. of Pd[P(OC N 0.2 g. of ZnCl 20 ml. of

and 6.0 g. of 'P(OC H The mixture is maintained at 100 C. for 22.5hours, while HCN is swept across the reaction at a rate of 0.2 ml./hour,measured as a liquid at 0 C. Infrared analysis shows a strong nitrileabsorption band at 2240 cm." which shows the presence of productsresulting from the addition of HCN to the double bond of Example XXIVThe reaction flask, as described in Example XXII, is charged with 1.35g. of Pd [P(OC H 1 0.2 g. of ZnCI 20 ml. of

CN, and 6.0 g. of P(OC H The mixture is maintained at 100 C. for 23.5hours while HCN is swept across the reaction at a rateof 0.1 ml./hour(measured as a liquid at 0 C.)

"Gas chromatographic analysis shows that the crude product containspeaks corresponding to a known sample of hydrocyanated 10 Example XXVThe reaction flask, as described in Example XXII, is charged with 1.35g. of Pd[P(OC H 0.2 g. of ZnCl 20 ml. of

and 6.0 g. of P.(OC H The mixture is maintained at C. for 22 hours whileHCN is swept across the reaction at a rate of 0.08 ml./hour (measured asa liquid at 0 C.).

Gas chromatographic analysis shows that the crude product contains peakscorresponding to a known sample of hydrocyanated ll COCHa Example XXVIThe reaction flask, as described in Example XXII, is glaargled with 1.35g. of Pd[(OC H 0.2 g. of ZnCl m of and 6.0 g. of P(OC H The mixture ismaintained at 100 C. for 22.5 hours, while HCN is swept across thereaction at a rate of 0.5 ml./hour, (measured as a liquid at 0 C.)

Gas chromatographic analysis shows that the crude product contains peakscorresponding to a known sample of hydrocyanated aka Example XXV II Thereaction flask, as described in Example XXII, is charged with 1.35 g. ofPd[P(OC N 0.24 g. of B(C H and 20' g. of 3-pentenenitrile. The mixtureis maintained at 100 C. while a mixture of N and HCN gas is swept acrossthe surface at a rate of 0.07 mL/hour ,(measured as a liquid at 0 C.)for 20 hours.

Gas chromatographic analysis shows that the crude product contains 4.64%adiponitrile.

Gas chromatographic analyses also shows that the crude product contains5.59% 4-pentenenitrile. The starting 3-pentenenitrile reagent containsno 4-pentenenitrile.

Example XXVIII The reaction flask, as described in Example XXII, ischarged with 1.35 g. of Pd[P(OC H and 20 g. of ibpfntenenitrile. Themixture is stirred for 3 hours at Gas chromatographic analysis showsthat the crude product contains 4.65% 4-pentenenitri1e.

In Examples XXIX to LII, the reaction flask, as described in ExampleXXII, is flushed with nitrogen, then charged with 20 g. ofS-pentenenitrile along with the catalyst system listed in the tablebelow. The reaction mixture maintained at the temperature indicated inswept with HCN nitrogen mixture at the flow rate and for the length oftime shown. The reaction products are analyzed by gas chromatographicanalysis. The legend for the products is as follows: A=adiponitrile;B=2-methylglutaronitrile; O=ethylsuccinonitrile.

Examples XXIX to XXXIX illustrate further the use of promoters for thecatalyst system in the hydrocyanation reaction. The preparation of thecatalyst system in situ is illustrated in Examples XL to XLV. The use ofa mixed alkyl-aryl phosphite ligand is illustrated in Example XLVI. Useof a phosphite ligand having 15 carbon atoms in each R group is shown inExample XLVII and use of phosphine ligands is illustrated in ExamplesXLVIII to LII.

of palladium and platinum, X is selected from the group consisting of Rand OR and R is selected from the class consisting of alkyl and arylgroups having up to 18 carbon atoms, and forming 4-pentenenitrile.

5. The process of claim 4 wherein there is present, in addition to thecompound of structure M(PX an acid of the group consisting of hydrogencyanide, trifiuoroacetic acid, hydrochloric acid and sulfuric acid.

6. The process of claim 4 wherein there is present,

TABLE 1 Reaction tempera- Flow, Time, Catalyst, g. ture, C. mL/hr. hrs.Products, percent Example:

XXIX P(l[P(OCnH5)3]4, 1.35; NlClz, 0.13; P(OC5H 3.1 100 0. 6 1011110655; B, 0.080 C, XXX Pd[P(OCeI'I5)3]4, 1.35; CeCh, 0.25; P(OC@H )3,3.1 100 0. 5 22 11,001.73; B, 0.31; C,

. 1 XXXI Pd[P(OCtH )3]i, 1.35; C012, 0.31; P(OC@H5)3, 3.1 100 A, 1.62;B, 0.65; C,

0.11 XXXII Pd[P(OCtH )3]4, 1.35; C(lCl2, 0.18; P(OCH5)3, 3.1 A2036;13,132; 0,

0.2 XXXIlI Pd[P (OCaH)a]4, 1.35; M0Cl2, 0.17; P(OC0H5) 3.1 100 0. 2 2114,011.55; B, 3.74; C,

.66 XXXIV Pd[P (005119314, 1.35; ZrCh, 0.23; P(OCH5)3, 3.1 100 0. 3 21A6678; B, 2.15; C, XXXV Pd{P(OCsH5)3]4, 1.35; ThClr, 0.37; P(OC0H5) 3.1100 0. 2 20 A, 11.41; B, 0.38; C,

0. XXXVI Pd[P(OCaH5)a]4, 1.35; ZrCl-r, 0.23; P(OC@H5)3, 3.1 100 0. 2 21Ab ldgg; B, 0.60; C, XXXVII Pd[P(OCflH5)3]-l, 1.35; A1013, 0.13;P(OC0H5)3, 3.1 100 0.2 21 A6412; B, 1.62; C,

.2 XXXIX Pd[P(Oc6I'I5)3]J, 1.35; C0012, 0.13; P(OCsH5)3, 3.1 100 0. 3 17A, 15426; B, 6.76; O,

1. XL PtlClz, 0.18; Fe, 0.06; P(OCeHs), 6.2 100 0.3 17 A, 46.21; B,2.64; C,

0. XLI PdClQ, 0.18; Zn, 0.07; P(OC@H5)3, 0.2 100 0. 3 A,10351; B, o 17,C,

0.0 XLII PdCly, 0.18; NaBHr, 0. 5; P(OCul-l5)3, 6.2 100 0. l 6 A, 1.75;B, 0.29 XLIIL ldClg, 0.18; Zn, 0.07; P(OCnH5), 7.0 100 0. 6 21 A, 1.82;B, 0.87; C, 0.32 XLIV PdClg, 0.18; A1, 0.1; B(CalI.-,)3, 0.3; P(OC@H5)3,6.2 100 0.2 21 A, 0.357; B, 0.42; U,

0.1 XLV PdClz, 0.18; Mg, 0.1; B(C0H5)z, 0.3; P(OCH5)3, 6.0 100 0. 2 21A, 0.020; B, 0.102 XLVI.-.. PdClz, 0.18; Z11, 0.1; P(OC H5)2 (OCaHts),5.5 100 0. 2 21 11,024.42; B, l C,

. 1 XLVII PdClz, 0.64; AI(C2H5)3 5 1111.; P(0C6H4CnH 9)3, 28 100 0. 7 21A, 2%.8; B, 14.12, C,

.2 XLVIII PdClz, 0.8; Zn, 0.6; ZnCh, 0.6; P(CH 5.2 80 0. 04 22 A, 35.06;B, 3.16; C,

1. 1 XLIX PdClz, 0.8; Zn, 0.6; P(CeH5)3, 2.6 80 0.1 21 A, 14.73; B,6.66; C,

2.84 L PdClz, 0.8; Zn. 0.6; P(C5H5)a, 3.9 80 0.3 21 A, 3 1936; B, 3.047;C,

. 3 L1 PdClg, 0.8; Zn, 0.6; ZnClg, 0.6; P(C4Hn)3, 5.0 80 0. 2 21 A,0.44; B, 0.26 L1I PdCl-z, 0.8; Fe, 0.6; P(C5H5)a, 5.2 80 0.07 21 A2,1.345; B, 0.368

The foregoing examples also illustrate the use of an excess of ligandsuch as an aryl phosphite or an aryl phosphine with the catalystcomplex. The molar ratio of the excess ligand to catalyst is at least2:1 and preferably at least 8:1.

For recovery of the hydrocyanation products, conventional techniques maybe employed such as crystallization of the product from solution ordistillation.

What is claimed is:

1. A process of isomerizing 3-pentenenitrile to 4-pentenenitrile whichcomprises contacting 3-pentenenitrile with a chloride of a metal of thegroup consisting of palladium and platinum, the metal having a valenceno greater than +2 at a temperature of from C. to 200 C. and forming4-pentenenitrile.

2. The process of claim 1 wherein the chloride of a metal is palladiumchloride.

3. The process of claim 1 wherein the chloride of a metal is platinumchloride.

4. A process of isomerizing 3-pentenenitrile to 4-pentenenitrile whichcomprises contacting in a reactor 3- pentenenitrile and a compound ofthe structure M(PX wherein M is a metal selected from the groupconsisting in addition to the compound of structure M(PX a cation of ametal selected from the group consisting of zinc, cadmium, titanium,tin, chromium, iron and cobalt.

7. The process of claim 4 wherein there is present, in addition to thecompound of structure M(PX a boron compound selected from the classconsisting of alkali metal and tetra (lower alkyl) ammoniumborohydrides, borohydrides of the structure B H wherein n is an integerof from 2 to 10 and B H Where m is an integer of from 4 to 10 and organoboron compounds of the formula B(R) wherein R is selected from the classconsisting of aryl radicals of from 6 to 18 carbon atoms, lower alkylradicals and cyano substituted lower alkyl radicals.

References Cited UNITED STATES PATENTS 3,347,900 10/1967 Gossel et a1.260465.3 3,407,223 l0/l968 Kominami et al. 260465.3

JOSEPH P. BRUST, Primary Examiner US. Cl. X.R.

